Inconsistent TIG? Gas better?

[Onoff]

I recently had cause to copy some special stainless steel "spring clips" from a 20 year old sample I had. Basically it's a scaffold staging clip with a lanyard. The sample I had is to go on an Imperial fitting originally. I re-designed it on CAD to fit over a metric bolt and had the U pieces water jet cut. My fabricator TIG welded a sample up and when I saw it I commented that I thought maybe the original had been gas welded. The sample had been fully welded and in fact lost some of the "meat" of the U. It was very discoloured so I was thinking maybe too much heat had gone in to it?

I asked therefore that they only be welded on two sides like the originals.

They have now all been TIG. Comparing them and in my opinion it seems to me there's not enough weld, enough penetration and the welding is generally inconsistent one to the other. My gut feel is that a better / more experienced TIG welded could have achieved better results akin to how the sample looks. They're going back to be corrected hopefully but am I being unfair to my fabricator on this? He was citing how fiddly they were but to me that's not an excuse for inconsistency:

The original sample, gas welded maybe?

Another view:

The fully welded sample - it's been rumbled and pickled:

Another view - you can see where the U has been eroded:

A line up of the TIG welded, finished items. Not welded all round, to me the welds look inconsistent, again these have been rumbled and pickled:

 

[Richard.]

In your favour that is not a fiddly or difficult job at all. The parts can all be turned to give optimum position, access is there to all sides and the walls look thick enough to take current well.
I can't really see the welds properly but you should expect subtle differences between them as they are welded by human hand. If they appear to be seriously different or bad quality then yes you should have them redone. The original item looks like it's been tacked with a mig. The tig weld will appear to be much smaller and neater probably stronger too.

 

[super noob]

If you want them brazed ask him to braze them? You can even get tig brazing filler rods

 

[Richard.]

If you want them brazed ask him to braze them? You can even get tig brazing filler rods

They are stainless steel. The best approach by far is to weld them.

 

[500e]

The right hand one of the 4 looks to be cracked on vertical spreading into horizontal

 

[Onoff]

Thanks for the comments. They must be welded rather than brazed.

Richard, you reckon the original was MIG'd, interesting. It just looked a gentler, less "aggressive" and more rounded weld.

The profile of the U's is 5mm x 5mm Gr316 btw.

A couple more shots here:

A "front" view. I'd incorporated a little recess into the "n" shape to hopefully give something to penetrate into:

On 3 assemblies (o/of 22 total) they've forgotten to weld the top side:

This one is inexcusable to my mind. How can the guy doing it be happy with it:

Just a random shot. How much weld there is across the 5mm seems to vary from one to the other:

Maybe I'm just being picky. I wasn't aware a small TIG weld is stronger than a larger MIG weld. If that's the case why is that please?

Cheers

 

[hotrodder]

Maybe I'm just being picky. I wasn't aware a small TIG weld is stronger than a larger MIG weld. If that's the case why is that please?

You're not being picky, the new samples are pretty awful and riddled with flaws including what looks like at least one cracked weld
The origional looks MIGed to me as well, generalising lots a decent TIG weld typically has better fatigue properties* than a decent MIG weld and while it's possible (quite easy) to produce a neatish MIG weld with poor fusion / LOF (lack of fusion) with TIG it's kinda the other way around i.e. if it looks good it usually will be and it's relatively difficult to produce an ugly weld that's sound and free of defects
The little recess you added isn't necessary, if you want them fully welded grinding a small relief where the red line makes more sense



* A large part of this is often down to things like weld profile and the transition from weld 'toes' into the base material i.e. larger/more convex weld = more of a stress riser [/gross generalisation]

 

[Onoff]

Thanks for all the comments. I had really high hopes for these, with them being designed on CAD, water jet cut etc that the finished articles would really look "something", at least as good as the original. The original btw was made by hand forming 5x5 bar I believe. (I did mull over having them cut from a solid block with a 3D water jet but have only made tentative enquiries on this so far). Sadly the new ones to my mind look a bit, well embarrassing without further work. Making a pig's ear from a silk purse etc. There's even multiple arc start marks on some.

 

[super noob]

Well I hope you haven't paid him for the work yet!

 

[Onoff]

When the welding issues are addressed to my satisfaction I'm after getting them media blasted to give the base material and weld a uniform finish. So far, as said above they've been pickled in acid (nitric?) to get rid of the weld discolouration then rumbled/tumbled to soften the edges etc.

Any suggestions? I thought sand or grit blasting maybe.

 

[Richard.]

Pickling paste and a buff up should do the trick.

 

[super noob]

acid should give a uniform finish anyway as it'll remove a couple of microns from the surface, tumble polishing with ceramics or bead blasting would give it a satin finish or if you want high shine then it'll have to be buffing on a wheel with a mixture of compounds

 

[hotrodder]

If you want a sample of what they should look like i'm not a million miles away (Bexley)

 

[Richard.]

I would definitely take HR's offer on that onoff. This will give you a good sample to hand over to your welding guy and say "I'd like another 50 to this standard pls".

 

[Onoff]

If you want a sample of what they should look like i'm not a million miles away (Bexley)

That would be incredibly decent of you! I wouldn't want to put you to any great trouble though especially at this time of year.

I could maybe drop off one on the ones they "forgot" to do all 4 welds on. Maybe pm me when would be convenient?

 

[Luke]

I'm surprised you're willing to keep working with the same people with an initial batch like that.

 

[Appyasme1]

Sorry guys.My job is repairing welding equipment,we have to make sure our equipment is turned out first class.The welds shown are a total discrace!!

 

[backpurge]

Just to echo the comments of the guys above, the weld quality is pretty diabolical, anyone who considers themselves proficient enough to charge for their services should produce something far better than you have got

 

[Onoff]

Just to add I've used this fabricator for coming up 30 years. Never, ever had an issue in the past with welding and had a lot of ali and st/st done over the years.

In fact their TIG welding IMHO WAS always superb. I think it's a case of key staff moving on.

 

[Appyasme1]

On off,you must be older than me!!!